Fixing the Rovio battery charging circuit

[Chris] was unhappy with the battery performance of his Rovio. It seems that he’s not alone, so he set out to reverse engineer the battery charging circuit to see if there was a fix. Boy is there, what he found is the diode above, apparently installed backwards when compared to the silk screen diode symbol. Now it’s entirely possible that the silk screen is wrong and this was fixed during assembly. We think that’s unlikely because if the closer of the two diodes was supposed to have the same polarity as the one next to it there should have been room to install them both in exactly the same orientation. [Chris] pulled out a soldering iron and changed the diode to match the silk screen. That fixed his problem and he’s now getting better performance than he ever has.

I recently had to replace some caps on an older mainboard… the polarity is marked out on the board so that you can’t really screw up (as long as you know how to read the thing).

I also love just looking at pcb board layouts to see if there is maybe something that isn’t on the board that there is room for. Can’t tell you how many times I’ve added things like extra usb slots to computers because the board was pinned for it but wasn’t put on because it was the lower end model of the same product line.

Parts like those are usually hand assembled so probably worker error. If that went to an AC power source then like it was installed it would have delivered half the power it was supposed to. It would have worked as a quarter wave AC – dc conversion instead of half wave.